During WW1 and WW11 all British binoculars that were used by the Armed Forces were stamped with the Ministry Broad Arrow.At the time of WW1 there was a shortage of binoculars, so the military 'bought in' a lot of binoculars. These binoculars could have been French, German, or from private individuals ect, wherever they could find them.

This binocular was used during WW I. On the front you see the "Broad arrow", which means that this binocular was purchased by the British Army.

On the right cover S1 is engraved, which stands for "High grade prismatic binoculars ". "M" stands for military and number 1735.

In one circle on the covers on the objective side you find "R sch 10/40" In the other "AM", which means the Air Ministry.It was formerly a department of the British government with the responsibility of managing the affairs of the Royal Air Force. It existed from 1.4.1914 to 1964.

So probably this binocular was used on an airfield in France during WW1